During the ten days I rented a full-size Pontiac, driving it nearly 1500 miles, I got to know it pretty well. The first few days were a voyage of discovery into the unknown, however. I had no manual for the car, and had to rely on the little symbols on the knobs, buttons and sliders to figure the car out. In the software business, most of us know that there's no such thing as an “obvious” symbol for anything. I think that the car manufacturers, as they manage the slow slide of the automobile interface from obvious and universal to original, incomprehensible and quirky, have a bit to learn about icons.
The best thing you can say about icons is that they do not have to be translated. You can use the same symbols in every country, which lowers Internationalization costs. It matters not that some of these icons will be cultural-specific. It matters not that some of them will make no sense to anybody. They just DON'T HAVE TO BE TRANSLATED.
Perhaps you'll understand why I'm working up such a snit when I tell you that my rented car had sixty icons visible from the driver's seat. Oh, maybe there were more somewhere; I counted sixty. The icons were not all different, mind you. In several cases, the same symbol was reused, FOR DIFFERENT FUNCTIONS. And most of them were pretty obvious, leaving maybe twenty as an exercise for the busy driver. I will reserve the cruise-control icons for a separate blog entry, they richly deserve it. Otherwise, my favorite icon was a button that looked a lot like the old symbol for the “enter” key, a sort of abstract indicator of a carriage return. This button turned out to be the “interact” button. If pressing any other button required you to make a choice, you pressed the “interact” button to go through your choices. If pressing a button required you to confirm you'd seen something, or if the car wanted to know you'd seen a warning message, you pressed the “interact” button. Quite a concept!